Improved artificial grindstone



sired degree of fineness,

UNITED STATES .enonen G. enisWoLn, on cnnsrnn connncrlcnr.

IM PVRVG'VEDI ARTIFIOIAL en'ij osToN E.

Specification forming part'of Letters ratent-N 0. 453 33, dated'Novemberfli), 1864.

To Jail whe m it may concern:

Be'it'known thet-I, GEORGE G, GRISWOLD,

of Chester, in the county of Middlesex, State of Connecticut, have invented, ,made, end'ap- 1 'bining. sand with hydraulic cement-to vform a substitute for theinatl'l'rel grindstcne, which substitute shall possess the advantages herein after fully set forth.

'l o enable those. skilled in the arts to nidke ,and nse my invention, I willdescribethe mode; T pursued by me in manufacturing the same;

I take common send and sifti'it to any de- I v I then thoroughly. incorporatethe sifted'sand with hydraulicce n ent and place the'product in a, mold; which mold corresponds in form and size to the artificial stone to be made. Themcld, with it's contents, is then placed in a screw-press, or a press operated by a-lever, by which pressure the sand and hydraulic cement are firmly united, and after being removed from'thepress 1 may be allowed to stand "a few days until thoroughly dry, when the artificial stone thus formed is ready for use.

may be The ednantag'es resulting iromthe menufec' ture of my improved grind'stone may be thus enumerated. The grindstoneis perfectly u-niform throughout as to grit. No pins occur,

as in the natural 'g'rindstone, and the same may be made as coarse or as'fine as desired,

while the cost will be found one-fourth that of theordinery stone."

In order that the center of or a centerfermedof iron and provided with prongs may be placed inthe mo1d,fand1d1ir-* ing the pressing operation the prongs will be inserted into the composition and remain firmly therein.

' I. do not intend toconfine my inventi-onsim 'ply to grindetbnes, as I din ewere that a, substitute for the common whetstonemay be inade in the same 1cnam;1e1': .v

Having thus described 1 my improvement, what I claim therei-nns new-and desireto secure 'by l'letter sletent, is-- -j Combining sand withhydraulic cement to form a substitute for the common grindstone, when'the saline shall be combined substantiallyas herein describedv GEORGE G; j GRISW'OLD. In presence of-- docnn rns DE-mson, HOMER SHAILI llLu p the grindstone formed,- acore is placed in the mold? 

